Studies on the Occurrence of Polyploidy and its Contribution to the Flower Plants Breeding. : IX. Cytological Observations on the Mechanism of Decreased Fertility in the Summer-flowering Tetraploid Cultivars of Gladiolus grandiflorus Hort.

Abstract

Some cytological observations were carried out to know the mechanism of decreased fertility in Gladiolus. Thirty cultivars were all tetraploid (2n=60). More or less univalent chromosomes appeared frequently during the meiotic division of PMC_s, resulting various-shaped abortive pollen and unreduced ones. Embryosacs in ovaries of some varieties well developed at one day before anthesis and the eggs were fertilized normally by artificial pollination. In other varieties, however, defective embryosacs were produced and degenerated soon before anthesis.